1. Field of the Invention
The present invention relates to directional alignment and alignment monitoring systems for directional and planar pattern omni-directional antennas.
2. Brief Description of the Related Art
Alignment of directional antennas is important in a competitive industry with customers expecting uninterrupted cell phone and other communications. See the reference paper “Impact of Mechanical Antenna Downtilt on Performance of WCDMA Cellular Network” also the paper “Impacts of Antenna Azimuth and Tilt Installation Accuracy on UMTS Network Performance” by Bechtel Corp, both of which are incorporated herein by reference.
Several types of metrology equipment are currently used to align directional antennas. These include standard construction tools such as levels and transits. By way of example, by locating a person at a distance from an antenna at a known heading, the antenna may be sited using a compass, GPS, survey, laser or transit or other optical means. Such methods require a technician or team of technicians to climb to the antenna, which is normally mounted at an elevated location, usually on a tower, and actively align and measure the antenna position directly, with their hands on the antenna. No devices are currently known that remotely monitor antenna alignment after installation or verify exact alignment during or after installation.
Hands-on alignment is a significant cost to owners of directional and omni-directional antennas and accurate information is crucial when relating to overall RF system design. Currently, there is no all-inclusive method to double check tower crew measurements. Each time a storm hits an area or a period of time passed dictates a need to re-verify alignment, a crew of technicians must climb to the antenna and physically check alignment of the antenna. The measurements are complex and made in a difficult environment high above the ground. If a mistake is made, there is no way to verify the alignment directly. Only by a study of antenna power distribution made by checking the area the antenna is servicing with radio test equipment and comparing the signal strength to a master can proper alignment be determined and this is a costly and time consuming process. Also, this method is indirect, as other factors besides alignment may affect signal strength.